Description

Bombus hypnorum has a short proboscis (tongue) and an rounded head. The thorax is uniformly ginger, the abdomen black and the tail white. Usually the first tergite (abdominal segment) has yellow colouration, at least on its sides. Males may have yellow hairs intermixed with the black fur on their faces. On the continent individuals with extended yellow colouration exist.[2]

Ecology

The bumblebee often lives near human settlements. The nest is quite large, 150 workers or more (according to some authorities up to 400). The species is a pollen storer, i.e. it stores pollen in separate cells and feeds each larva individually, instead of storing the pollen directly in the larval cells. It visits flowering plants as Rhododendron, cherry, grape hyacinth and, in the north, Vaccinium.[2]

The tree bumblebee defends its nest in a very pro-active manner. If disturbed, a large number of very aggressive workers emerge from the entrance to defend the nest. They will fly at high speed around the entrance to the nest, in order to scare away possible attackers. In this state, they may well sting unprovoked. For this reason, the tree bumblebee might end up in conflict with humans if it establishes its nest in human buildings. However, if left undisturbed, the tree bumblebee is quite peaceful.